Surgical drain



Feb. 13, 1962 w. T. HEYER 3,020,913

SURGICAL DRAIN Filed July 15. 1958 INVENTOR.

WILLIAM 7T HEYEE ATTDRN United States Patent 3,020,913 SURGICAL DRAIN William T. Heyer, 411 N. Wilson Ave., Pasadena, Calif. Filed July 15, 1958, Ser. No. 748,652 9 Claims. (Cl. 128-350) This invention relates to a surgical drain.

There is need for a surgical drain provided with antibackflow means which can be used to drain fluids from certain regions of the body. It is often desirable for these drains to be left in the body for considerable periods of time, perhaps even permanently, and their installation frequently requires quite elaborate surgical techniques. Because their function is to relieve distressing (sometimes even fatal) symptoms by draining ofi fluids which ought not to be where they are, it is essential that the anti-blackflow device be reliable because, if, instead of draining the fluids, it merely provides a supply conduit for introducing more fluids from still another source, a

bad situation could be rendered worse, or even fatal.

Furthermore, should the device break down or misfunction, then the elaborate surgical techniques must be re peated, with the consequent risk inherent in surgery.

Thus a suitable surgical drain must be long-lived, rugged, and simple in construction in order to eliminate the need for frequent replacement thereof. It must also be dependable, because a persons life may hinge on its action.

As an example, the condition known as hydrocephalus occurs, most frequently in infants and young children, wherein fluids secreted from the brain tissues gather in the skull, thereby dilating the ventricles of the brain and grotesquely enlarging the head. It has long been known that the condition can be alleviated by tapping off the fluids, but in the past this has been accomplished only at intervals and not by continuous drainage, because reliable means for continuous drainage did not exist.

The alleviation of the symptoms of hydrocephalus has had to await the invention of a surgical drain which could be planted and left inside the child, one end in the brain and the other end at some other location in the body able to receive and dispose of the fluids, such as auricle of the heart. Obviously, because the heart is filled with fluid, anti-backflow means are essential, lest the blood flow from the heart into the brain with potentially fatal results.

It is an object of this invention to provide a simple, rugged, long-lived and dependable surgical drain provided with anti-backflow means for draining cavities in the human body. This valve is particularly suitable for a ventriculo-venus shunt tube to drain olf fluids from the brain, although it can also be used to drain other cavities to regions both inside and outside the body.

A surgical drain according to the invention comprises a flexible tube having a central axis, the tube having an inner and outer wall. The inner wall defines an axial interior passage. Inlet means, which are preferably holes between the two walls, connect the passage to the outside of the tube at one axial location to let fluid drain into the passage. Unidirectional outlet means are axially spaced from the inlet means and from the ends of the tube. The outlet means comprise an axial slit that eX- tends through the tube between the walls, the slit having substantially planar faces lying in a plane that includes the axis, the faces being substantially co-planar. There is no substantial spacing between the faces when the tube is undistorted, and the slit is therefore closed when there is equal pressure on both walls. The slit opens to let fluid escape from the passage when the pressure of fluid in the passage sufficiently exceeds the pressure on the outside wall.

According to one preferred but optional feature of the invention, all parts of the tube are made of material which has substantially the same resilient flexural strength and hardness as human tissue.

According to still another preferred but optional feature of the invention, a substance, preferably molybdenum disulfide, is impregnated into at least one face of the slit to prevent the faces from adhering to each other, thereby assuring that the slit will not close up because of adhesion between the co-planar faces.

The foregoing and other features of my invention will be fully understood from the following detailed description and the accompanying drawings of which:

FIG. 1 is a front elevation of part of a human body, showing a drain in accordance with this invention, extending from the brain to the heart;

FIG. 2 is a partial view in elevation showing the drain of FIG. 1, and a partial cross-section of the facial artery, jugular vein, and entrance to the heart; and

FIG. 3 is an enlarged detail view, partially in crosssection taken at line 33 of FIG. 2.

In FIG. 1 there is shown a flexible surgical drain 10 which is an elongated tube 10a that passes through a facial artery 11 into the ventricles 12 at the outer surface of the brain 13. At this point the catheter end 14 of the tube receives in axial passage 21c the secreted fluid of the brain 13 which is desired to be drained off. The tube 10a then passes through the facial artery 11 and enters the internal jugular vein 15 through which the tube passes from the head 16 down through the neck 17 and ends approximately half-way into the right auricle of the heart 18 where the fluid is discharged near the distal (valve) end 19 of the tube. The fluid is then disposed of by the body in passing through various outlet portals of the heart 20 and into the bloodstream.

FIG. 2 shows a drain 10 oriented on a horizontal axis, but it will be understood that in actual use said tube bends as shown in FIG. 1.

Inlet means comprises a series of small openings 21 that extend between the inner and outer walls 21a, 21b, respectively, of the tube so as to connect axial passage 210 to the outside of the tube and allow fluid to enter into the tube. A facial artery 11 is cut at some convenient place where the catheter end 14 is inserted into the ventricles 12.

Special care is taken in forming the tip 22 of the distal end 19 of the drainage tube 10. Tip 22 is conical in shape with a rounded apex. In experimental installations of this device, it has been found desirable to shape the tip as shown, and to have it terminate in the ventricle. With such an arrangement, there has so far been no indications of tissue growth around the distal end of the drain. Uni-directional outlet means comprise a small slit 24 extending axially in the wall near the distal end 19 of the drainage tube 10, but spaced from the extreme end, and allow the fluid to flow out when the differential fluid pressure across the slit 24 reaches a specific value, for example, 0.1 pound per square inch.

PEG. 3 shows the slit 24 penetrating radially through the tube, interconnecting the walls. it has a pair of flat faces which lie in planes that include the central axis of the tube, and they are substantially co-planar. No material is removed in cutting the slit. Centered in the tip 22 of the distal end 19 is a solid cylinder (sometimes called a backing member) 25 of the same material as the drainage tube 10. This backing member is optional. This cylinder extends axially beyond both ends of the slit 24. The inner wall of the tube clears the cylinder 25, leaving an annular spacing 0.005" wide around the cylinder. This spacing has been found desirable because it eliminates clogging of the tube. Bits of tissue are frequently sloughed off along with the fluids 3 to be drained, and if the tube fitted much more closely to the cylinder 25, tissue might tend to collect there and destroy the function of the valve.

If the fluid pressure within the right chamber of the heart becomes greater than the combined fluid head pressure in the drainage tube and the fluid pressure in the ventricles, the edges of the slit meet and shut off any backfiow from the heart into tube 10.

The backing member is provided to keep the valve portion of the drain from folding or kinking. If the tube were to kink, the slit could remain open to backflow. It is not necessary for the tube to make a snug contact fit with the backing member in order for the backing member to perform its function. In fact, for the reason stated above, a close fit between the tube and the backing member ought to be avoided, and in many cases the backing member can be eliminated entirely, because kinking is not always a problem.

The stiffness and hardness of the material used for the drainage tube should be comparable to that of human tissue. A recommended material is cured silicone rubber, made by Dow-Corning Corporation, Midland, Michigan, and sold under the designation 8-2000. The outer diameter of the tube is about 0.085, the diameter of the internal passage 210 is 0.055".

A suitable procedure for making the distal end 19 and the tip 22 is to insert the solid cylinder 25 whose outside diameter is about 0.045 into the tube at its end, hold the cylinder in the tube in position by pinching on the tube. Then, using a syringe, uncured silicone rubber can be squirted into the tube around the end of the cylinder, and when the syringe is withdrawn, a blob of rubber is left hanging onto the end of the tube. This uncured rubber is preferably compounded with powdered barium sulphate, which is impervious to X-rays. The location of the tip in the heart can later be determined by visualizing this tip. The tube end is then placed into a mold cavity and held there for about five minutes at 480 F. to vulcanize and set the tip 22. It is then removed from the mold and cured to remove gases for several hours at about 480 F. After cooling, the tip is ground down to size. The preferred shape is substantially conical, and slightly convex. This shape enables the drain to be inserted easily into veins, and discourages adhesion of tissues thereto.

Slit 24 is then cut to a length of about 0.125" axially, through the wall of the tube. A substance, for example molybdenum disulfide, is then impregnated into the wall at the slit 25 to keep the slit faces from adhering together. Because no material is removed in making the slit, there may be some tendency of the slit to remain closed because of molecular adhesion, unless the impregnation is provided as a precaution.

The tube can be tested for operation by filling it with water, and being sure that it drains down to a remaining column of water about 6 cm. high.

It is to be understood that more or fewer openings 21 could be provided, and also more than one slit 24. It is also within the scope of this invention to provide a snug fit between the tube and the backing member 25, although this is ordinarily not preferred.

This invention is not to be limited to the embodiment shown in the drawings or described in the description, where it is shown only as an example, and not as a limitation.

I claim:

1. A surgical drain for the removal of fluid from a body cavity comprising: a flexible tube having a central axis, and a concentric inner wall and outer wall, said inner wall forming an axial interior passage therein, inlet means connecting the passage with the outside of the tube at at least one axial location so as to permit fluid to drain into the passage, and uni-directional outlet ing an axial slit extending through the tube between the walls, said slit having substantially planar faces lying in a plane which includes the axis, said faces being substantially coplanar, said slit being opened when fluid pressure is greater on the inner wall than on the outer wall, and closed when the pressure differential is reversed, said slit having no substantial spacing between the faces, and therefore being closed when the tubing is in its undistorted condition with equal pressure on both walls, and a backing member within said passage disposed axially opposite the slit so as to be contactable by the inner wall to reduce the tendency of the wall to kink at the slit, and an end wall closing the tube at the opposite side of the slit from the inlet means.

2. Apparatus according to claim 1 in which the inlet means comprises a plurality of holes between the walls of the tube.

3. Apparatus according to claim 1 in which a substance is impregnated into at least one face of said slit to prevent said faces from adhering to each other.

4. Apparatus according to claim 1 in which the outer periphery of the backing member and the inner wall adjacent to the backing member are both circular cylinders there being an axial spacing between the said backing member and said inner wall.

5. Apparatus according to claim 1 in which the inner Wall is spaced from the periphery of the backing memher.

6. Apparatus according to claim 5 in which the inlet means comprises a plurality of holes extending between the walls of said tube.

7. Apparatus according to claim 5 in which a plurality of said axial slits are provided at substantially the same axial location in said tube.

8. A surgical drain for the removal of fluid from a body cavity comprising: a flexible tube having a central axis, and a concentric inner wall and outer wall, said inner wall forming an axial interior passage therein, inlet means connecting the passage with the outside of the tube at at least one axial location so as to permit fluid to drain into the passage, and uni-directional outlet means at a location spaced axially from the inlet means and from the ends of the tube, said outlet means comprising an axial slit extending through the tube between the walls, said slit having substantially planar faces lying in a plane which includes the axis, said faces being substantially co-planar, said slit being opened when fluid pressure is greater on the inner wall than on the outer wall, and closed when the pressure differential is reversed, said slit having no substantial spacing between the faces, and therefore being closed when the tubing is in its undistorted condition with equal pressure on both walls; molybdenum disulfide being impregnated into at least one face of said slit to prevent said faces from adhering to each other, and an end wall closing the tube at the opposite side of the slit from the inlet means.

9. A surgical drain for the removal of fluid from a body cavity comprising: a flexible tube having a central axis and a concentric inner wall and outer wall, said inner wall forming an axial interior passage therein, inlet means connecting the passage with the outside of the tube at at least one axial location so as to permit fluid to drain into the passage, unidirectional outlet means at a location spaced axially from the inlet means and from the ends of the tube, said outlet means comprising an axial slit extending through the tube between the walls, said slit having substantially planar faces lying in a plane which includes the axis, said faces being substantially coplanar, said slit being opened when fluid pressure is greater on the inner wall than on the outer wall, and closed when the pressure dilferential is reversed, said slit having no substantial spacing between the faces, and therefore being closed when the tubing is in its undistorted condition with equal pressure on both walls, an end wall closing the tube at the opposite side of the slit from the 5 6 inlet means, all parts of the drain being made of a ma- 2,876,773 Witz Mar. 10, 1959 terial which has substantially the same resilient flexural 2,969,066 Holter et a1. Jan. 24, 1961 strength and hardness as human tissue, and molybdenum disulfide impregnated into the faces of the slit to prevent FOREIGN PATENTS said faces from adhering to each other. 321174 Denmark 1923 825,924 Germany Dec. 27, 1951 References Cited in the file of this patent OTHER REFERENCES UNITED STATES PATENTS Circulation, 1952, vol. 5, A Technic of Vascular 274,447 Kenm'sh Mar. 20, 1883 Catheterization with Small Plastic Catheters, by Schnabel 2,867,213 Thorn-as Jan. 6, 1958 10 et ad. (page 257 required.) (Copy in 128-205.) 

